Flow rate regulators already exist in a variety of designs. With the aid of such flow rate regulators the maximum flow rate of a fluid per unit of time is supposed to be equalized independently of the potential pressure fluctuations and is supposed to be set at a defined value. Insofar as the fluid concerns, for example, drinking water conveyed in a drinking water line, a jet regulator may also be mounted downstream of such a flow rate regulator on the water spout of a plumbing outlet fixture. The jet regulator is supposed to produce a homogeneous, non-splashing and optionally also sparkling soft water jet. Since, however, the pressure losses caused, on the one hand, by the flow rate regulator and, on the other hand, by the downstream jet regulator, may add up in such a way that the downstream jet regulator does not have an adequate amount of water, the upstream flow rate regulator can also have a negative impact on the function of the downstream jet regulator—especially in the case of low pressure conditions. Therefore, in such areas, where, as a rule, only low water pressure prevails, a flow rate regulator can have such a negative impact on the available volume of water, that it is not practical to install such flow rate regulators in such areas. This drawback may be further intensified, if so-called booster pumps are used in order to increase the water pressure. These booster pumps result in a high pressure that increases even more the prevailing pressure differentials and appears to suggest all the more the installation of an equalizing flow rate regulator.
The applicant's German patent document DE 10 2005 011 947 A, which was filed before the present patent application, but was not published until after the present patent application, describes a flow rate regulator which allows a change in the maximum rate of flow. The previously described flow rate regulator exhibits in its control housing a passage channel, in which there are two regulating devices, which are arranged one behind the other in an elongation of the passage channel, comprise an annular restrictor and a central regulating core, and are designed for different flow rates or different pressure ranges. In this context the regulating device, which is designed for the lower flow rate and/or the lower pressure range, has at least one bypass channel or a similar passage opening, which can be opened and closed, and is opened for a higher flow rate and/or a higher pressure range and closed for the lower flow rate and/or the lower pressure range. Therefore, this flow rate regulator, described in the earlier publication, has two regulating devices, which are designed for different flow rates and/or different pressure ranges. For the lower flow rate and/or the lower pressure range the at least one passage opening is closed to the regulating device, designed for the lower flow rate and/or the lower pressure range, so that the flow medium—for example, water—must pass both the flow path between the regulating core and the restrictor for the higher flow rate and/or the higher pressure range and also the flow path between the regulating core and the restrictor of the regulating device for the lower flow rate and/or the lower pressure range. At the same time the characteristics of the flow rate regulator, described in the earlier publication, are set by the regulating device, designed for the lower flow rate and/or the lower pressure range.
For the higher flow rate and/or the higher pressure range, the at least one passage opening is opened to the regulating device for the lower flow rate and/or the lower pressure range, so that the flow medium—for example, water—can pass only the flow path between the regulating core and the restrictor of the regulating device for the higher flow rate and/or the higher pressure range, but not the flow path between the regulating core and the restrictor of the regulating device for the lower flow rate and/or the lower pressure range. Rather, it bypasses the regulating device for the lower flow rate and/or the lower pressure range through the passage opening. In this case the characteristics of the flow rate regulator, described in the earlier publication, are defined only by the regulating device for the higher flow rate and/or the higher pressure range. Thus, the maximum flow rate and/or the anticipated pressure range can be changed easily and quickly by opening or closing the passage opening, provided in German patent document DE 10 2005 011 947 A.
The characteristics can be changed with the flow rate regulator in German patent document DE 10 2005 011 947 A, but even the use of this flow rate regulator is less advantageous in areas where temporally and/or locally extreme pressure differentials and pressure fluctuations prevail.
Applicant's German patent document DE 20 2004 008 281 U1 discloses an additional flow rate regulator of the genre described in the introductory part. In order to be able to consider in the case of a flow rate regulator, which is inserted in the water inlet of an instantaneous water heater, the seasonally dependent temperature differentials; to guarantee a higher water flow rate, for example, in the summer when the inflowing tap water is usually already warmer than in the winter; to adjust the outflowing water to the same temperature; and to be able to change additionally the maximum flow rate with a low degree of sophistication, the flow rate regulator, which is disclosed in German patent document DE 20 2004 008 281 U1 of the prior art, exhibits an inner section of the housing that can be moved in relation to the restrictor in the regulator housing. The inner section of the housing can be operated by way of a control element, which protrudes outwards on the outer periphery of the inner section of the housing. The inner section of the housing on both sides of its control element is tightly encompassed by an outer section of the housing. The outer sections are arranged so as to be stationary in relation to one another. The inner section of the housing bears the conical regulating core, so that this conical regulating core can be moved in relation to the restrictor in such a way that, due to the conicity of the regulating core, the control gap between the restrictor and the regulating core changes (and with it, the maximum flow of volume of the flow rate regulator). Since the inner moveable section of the housing is tightly encompassed by the outer sections, and since the control element on the inner section of the housing protrudes outwards, the volume flow of the flow rate regulator known in the prior art can be easily changed without having to disassemble this flow rate regulator.
Because the outer sections of the housing that tightly encompass the inner section of the housing are arranged so as to be stationary in relation to each other, a displacement of the inner section of the housing and a displacement of the regulating core, borne by said inner section, and a change in the volume flow, do not automatically result in a change in the overall length of the flow rate regulator, which is disclosed in German patent document DE 20 2004 008 281 U1 of the prior art. Of course, these features do change the maximum flow rate in the flow rate regulator, disclosed in German patent document DE 20 2004 008 U1 of the prior art, but in the case of this flow rate regulator excessive pressure differentials can also have a negative impact on any optional downstream jet regulators or similar functional units.
A flow rate regulator having a multipart control housing is previously known from U.S. Pat. No. 4,867,198. A regulating core around which a fluid circulates and which conically tapers in the direction opposite the fluid flow is mounted in a downstream housing part. This regulating core cooperates with a flow restrictor, made of elastic material, which has the shape of a perforated plate and is affixed in a housing part on the supply flow side. An axial relative motion of the housing parts with respect to one another may be used to determine and specify the extent to which the conical control element projects into the orifice in the flow restrictor having the shape of a perforated plate. When the flow restrictor is deformed as a result of the pressure from the flowing fluid, the flow restrictor is able to move farther in the direction toward the regulating core in such a way that the annular gap remaining between the flow restrictor and the regulating core is further contracted. Since the annular gap may be modified on the one hand by an actuation of the housing parts relative to one another, and on the other hand by the pressure from the flowing fluid, the maximum throughput of the previously known flow rate regulator may be varied as needed and limited to the desired flow rate per unit of time.